Stop means for sewing machine



W. M. FARLEY STOP MEANS FOR SEWING MACHINE 2 Sheets-Sheet 1 Filed Sept. 9, 1954 ATTORNEYS v pril 29, 1958 W. M. FARLEY 2,

STOP MEANS FOR SEWING MACHINE Filed Sept. 9, 1954 2 Sheets-Sheet 2 IN VENTOR I W4 7 256/ M Z a/ /e5/ ATTORNEYD United States Patent STOP MEANS FOR SEWING MACHINE Application September 9, 1954, Serial No. 454,967

8 Claims. (Cl. 112-219) This invention relates to a stop mechanism for a sewing machine to automatically stop the sewing machine whenever an improper sewing operation occurs at the sewing station and is of particular importance where a plurality of automatic sewing machines are tended by a single operator.

Heretofore, because the operators attention has to be divided among the plurality of machines, it has been impossible for his attention to be directed immediately to that machine where an improper sewing operation occurs due to, for example, the needle or bobbin thread breaking or having improper tension therein, or exhaustion of the material being sewn. This results in the machine continuing to run and forming an imperfect stitch or no stitch at all if a thread is broken, thereby creating waste material and lost time. i

The present invention overcomes these disadvantages by providing a stop mechanism which is responsive automatically to stop any of a plurality of stitching malfunctions which may develop. This is accomplished by detecting a variation in the linear speed of the needle'thread when an improper sewing operation occurs. I have discovered that the rate of linear movement of the needle thread is indicative of the sewing operation being performed at the sewing station and whenever improper stitching is being performed at the sewing station due, for example, to a break therein, the failure of the needle thread to be drawn into a proper stitch formation be- 5 cause of improper tension or a break in the bobbin thread, or an exhaustion of the material beingsewn the rate of linear movement of the needle thread is decreased.

According to my invention I provide a novel governor which is. positioned in the path of and driven by the 50 needle thread so as to be responsive to the linear movement thereof and I control the driving means of the sewing machine by a control circuit having a self-contained switch means which is actuated by the governor. So r long as the linear movement of the needle thread is atthe established rate to carry out a proper stitching operation, the governor and switch controlled thereby maintain the control circuit in a driving position. Whenever the linear rate of movement of the needle thread is decreased for any reason indicating an improper sewing operation, 0 the governor speed is decreased and said switch actuated to render the control circuit operative to immediately stop the sewing machine and automatically stop the improper sewing operation until the operator can correct the trouble thereby avoiding waste. 65

A feature of the invention resides in controlling the operation of the sewing machine in accordancewith variations, of the linear speed of the needle thread as maybe occasioned by an improper sewing operation due to breakage or improper tension in the needle or bobbin threads or in the exhaustion of the material beingsewn.

Another feature of the invention resides in the pro- 2,832,303 Patented Apr. 29, 1958 vision of a novel thread driven governor and self-contained switch means actuated thereby to control the machine.

Other features and advantages of the invention will be apparent from the specification and claims when considered in connection with the drawings in which:

Figure 1 shows a sewing machine with the stop means thereon.

Fig. 2 is a detailed view of the stop means.

Fig. 3 is a detailed view of another form of switch.

Fig. 4 is a diagrammatic circuit arangement showing the stop means in the control circuit for the sewing machine.

In accordance with the present invention a novel sewing machine stop mechanism is provided for automatically stopping the sewing operation whenever improper stitching resulting from a variety of common causes of malstitching occur at the sewing station so that spoilage and lost time are materially reduced. While the stop mechanism of my invention may be built in as part of the sewing machine, it is herein illustrated as an attachment which is adaptedto be mounted on or fitted to existing machines.

As shown in Figs. 1 and 4, my invention is illustrated as being applied to a sewing machine 12 of usual construction having a drive motor 34 and clutch means for driving the machine and a suitable controllersuch as a foot pedal 36 for engaging or disengaging the drive means for starting and stopping the operation of the sewing machine.

In the preferred form of the invention, a novel governor 10 is fixed to the arm portion 11 of the sewing machine 12 by means of a projecting frame member. 13 which is provided with an aperture 14. A tensioning device 15 and an adjustable bracket 16 for supporting a self-contained switch means 17 are mounted on theframe member. The tensioning device 15 consists of the usual disk members 15a and 15b and adjusting spring 15c with thumb screw 15d for adjusting the tension of the needle thread.

A spindle 18 forming the rotatable axis of the gov ernor extends through the aperture. 14 in the frame member 13 and is supported thereon in a vertical position by a bushing 19 having upper bearing members 20 and lower bearing members 21 secured therein for freely rotatably mounting the spindle 18 on the frame.

The lower end of the spindle 18 projects below the frame and is located in the path of movement of the needle thread T as it moves from a supply, not shown, to the needle of the sewingmachine so as to be driven thereby as the thread moves during the sewing operation. If desired, a grooved pulley 22 may be mounted on the lower end of the spindle to be engaged by the threadto drive the spindle in accordance with the linear speed of the'thread.

I have discovered that the linear speed of the thread during a normal sewing operation remains constant and I have also discovered that the linear speed of the thread decreases during malformation of stitches or other defects in the stitching operation. For example, the spindle stops when the needle thread breaks and is not pulled through by the sewing operation. Also, the speed of the needle thread drops when, due to exhaustion, breakage or lack of proper tension in the bobbin thread, the needle thread is not drawn into proper stitch formation. Also, the speed of the needle thread drops when the material being sewn becomes exhausted and the bobbin thread does not draw the same amount of needle thread for each stitching operation. These defects in the stitching operation arecomrnon occurrences and produce waste in the imperfectly stitched material unless quickly detected.

Suitable guide means 23, 23a and 24 direct the needle thread from the supply (not shown) to and from the tension means 15, to the pulley 22 and to the usual sewing machine tensioning means. 25. The thread is then threaded to the take-up arm and to the needle in the usual manner. With the thread thus positioned, the needle thread looped about the pulley 22 remains taut to rotate the spindle 18 .in accordance with the linear speed of the thread whenever the sewing machine is performing a stitching operation.

The governor has a slideable sleeve 26 mounted on the upper end of the spindle to be rotatable therewith. Extending transversely of the slidable sleeve 26 and fixed thereto is a bar 27 having pivotally connected to its end portions a pair of depending links 28 and 29 having weights 30 at the lower ends thereof. 'The illustrated weights 30 on said depending links 28 and 29 are in the form of balls .adjustably mounted at the ends of said links. Although only two such links are illustrated, it is understood, however, that the use of other than two links may be used if so desired. Located between said transversely extending bar 27 and the ends of the links 28, 29 and fixed to the spindle at an intermediate portion thereof is a second transversely extending bar 31 having depending connecting links 32 and 33 pivotally connected by one end to the end portions of said second bar and at the other end to an intermediate portion of the weighted links 28, 29 as shown in Fig. 2.

Thus, when the spindle 18 is rotated, the weighted links will move outwardly due to centrifugal force and, because of the location of thebar 31 and links 32, 33, will cause the bar 27 and sleeve 26 to move upwardly on the spindle in accordance with the speed of the spindle.

Cooperating with the governor to control the sewing machine is the self-contained switch means 17 which is secured to the bracket 16 mounted on the frame so as to coact with the sleeve 26. As illustrated in Fig. 2,, the switch is a microswitch and an actuator 17a for the switch extends over and is contacted by aball-point portion 26a of the sleeve 26 in a substantially friction-free contact to move the actuator between the solid line position in which .the switch is normally closed and the dotted line position in which the switch is open.

Theposition of the switch and the operative lever ,armof the actuator 17a with relation to the sleeve 26 can be readily varied by adjusting the position of the bracket 16 by means of adjusting nuts 16a, 16b and by adjusting the switch on the bracket by means of screws 17b so that an accurate and versatile controlof the sewing machine can be obtained. i

In the form of the invention shown in Fig. 3, the controlswitch is a mercury switch 117 carried by an actuator lever 117b pivotally mounted on the bracket 16. The actuated lever is provided with adjustable weights 118 at the other side of the pivot whereby operation of the switch can be adjusted.

- The control of the sewing machine by the governor controlled switch is accomplished by connecting the switch in the drive control circuit therefor. While the sewing machine drive may take many forms, in the illustrated form'of the invention the electric driving motor 34 and suitable clutch means 35'for connecting the same to the usual drive of a sewing machineare utilized.

The clutch is'controlled by a controller or actuator in the form of a foot pedal 36 which is operatively connected to the.clutch 35 by a linkage connection 36a and bell crank 36b. A spring 37 connected to one end ofthe lever the connected down to driving position. The detent is controlled by a solenoid a connected'in the control circuit which includes a pair ofleads 38 and 39 connecting to a source of j energy, a normally open switch 41 controlled by the peda 36, and the normally closed switch 17 which are connected in series in the circuit. A normally open cut-off switch 42 is shunted around the normally closed switch 17 by conductors 43 and 44 so that an operator may manually actuate the control circuit to stop the sewing operation when necessary while the switch 17 is held open by the governor.

When it is desired to start a sewing operation the machine is threaded and the sewing operation set up. The pedal is then depressed causing the normally open switch 41 to close the circuit to the solenoid. The pedal is held closed until the sewing operation has started at which time the governor, operated by the thread passing to the sewing station, opens the switch 17. When this switch opens, the solenoid is deenergized and the detent springs back into position to hold the pedal in driving position. Should the linear speed of the thread passing to the sewing station decrease because of any of the malfunctionings set forth above, the governor sleeve 26 will be lowered causing the switch 17 to close the circuit to the solenoid which will retract the detent and permit the pedal to move into its raised position. Movement of the pedal to raised position will not only release the clutch but also open the circuit at switch 41 and the drive for the machine cannot be initiated until the difficulty is corrected and the pedal again moved to driving position.

From the foregoing it will be seen that the present invention provides an improved sewing machine stopping device embodying a novel governor responsive to the variation in the linear speed of the needle thread for stopping the sewing machine upon various defects in the stitching operation, thereby preventing waste of material and the saving of time and increasing production by the machine.

Variations and modifications may be made within the scope .of the claims and portions of the improvements may be used without others.

I claim: 7

l, A stop mechanism for a sewing machine to automatically stop the sewing operation whenever improper stitching occurs comprising'a governor having a rotatable spindle, a slidable sleeve on said spindle and rotatably mounted therewith, depending weighted links secured to said sleeve, a bar fixed to said spindle below said slidable sleeve having depending links connected at one end thereto and connected at the other end to an intermediate portion of said-weighted links, means for mounting said governor on asewing machine in the path of the needle thread to be engaged thereby and be responsive to the linear speed thereof, so that the centrifugal force imparted to the weighted links due to the rotation of the :spindle by the needle thread causes the slidable sleeve to move upwardly on'said spindle, and a control circuit having a separate self-contained switch means having enclosed circuit making and breaking means actuated by said slidable sleeve and rendered operative thereby to stop-the sewing operation whenever the linear speed of the .thread is decreased due to an improper stitching operation.

2 A stop mechanism for a sewing machine to automatically stop the sewing operation whenever improper stitching occurs comprising a frame means adapted to be mounted on a sewing machine, a bushing having upper and-lower bearing members secured thereon, a rotatably mounted spindle extending through said bushing and supported by said bearings, a portion of said spindle extending below said frame and into the path of the needle thread to be driven thereby, tension means mounted on saidframe for tensioning the needle thread passing to the spindle, control means positioned on the other end of said fspindle and'responsive to'the speed thereof, and a circuit having a separate self-contained switch means having enclosed 'circuit making and breaking means actuated by said control means and rendered operative thereby to stop the sewing operation whenever the linear speed of the thread and the spindle driven thereby is decreased due to an improper stitching operation.

3. A stop mechanism for a sewing machine to automatically stop the sewing operation whenever improper stitching occurs comprising a frame means mounted on a sewing machine, a bushing having upper and lower bearing members secured therein, a rotatably mounted spindle extending through said bushing and supported by said bearings, a portion of said spindle extending below said frame, drive means fixed to said portion and positioned in the path of the needle thread to be engaged and driven in response to the linear speed thereof, a sleeve slidably mounted on the upper end of said spindle and rotatable therewith, weighted links secured to said slidably mounted sleeve, a bar fixed to said spindle intermediate the ends thereof, depending link means having one end thereof pivotally connected adjacent the ends of said bar and having the other ends thereof pivotally connected to an intermediate portion of the weighted links so that the centrifugal force imparted to the weighted links due to the rotation imparted to the spindle by the linear move ment of the needle thread passing the drive means causes the slidable sleeve to move upwardly on said spindle, and a circuit having a separate self-contained switch means having enclosed circuit making and breaking means actuated by said slidable sleeve and rendered operative thereby to stop the sewing operation whenever the linear speed of the thread is decreased due to an improper stitching operation.

4. A stop mechanism for a sewing machine to automatically stop the sewing operation whenever improper stitching occurs comprising a frame means mounted on a sewing machine, a bushing having upper and lower bearing members secured thereon, a rotatably mounted spindle extending through said bushing and supported by said bearings, a portion of said spindle extending below said frame, drive means fixed to said portion, tension means mounted on said frame for tensioning the needle thread passing to the drive means and said drive means positioned in the path of the needle thread and responsive to the linear speed thereof, a sleeve slidably mounted on the other end of said spindle and rotatable therewith, dependent weighted links secured to said slidably mounted sleeve, a bar fixed to said spindle intermediate the ends thereof, dependent link means having one end thereof pivotally connected adjacent the ends of said bar and having the other ends thereof pivotally connected to an intermediate portion of the weighted links so that the centrifugal force imparted to the weighted links due to the rotation imparted to the spindle by the linear movement of the needle thread on the drive means causes the slidable sleeve to move on said spindle, and a circuit having a separate self-contained switch means having enclosed circuit making and breaking means actuated by said slidable sleeve and rendered operative thereby to stop the sewing operation whenever the linear speed of the thread is decreased due to an improper stitching operation.

5. A stop mechanism for a sewing machine to automatically stop the sewing operation whenever improper stitching occurs comprising a frame adapted to be mounted to a sewing machine, a governor including a rotatable spindle mounted on said frame in the path of the needle thread and driven in response to the linear speed thereof, a rotatably and slidably mounted sleeve portion having a ball point positioned on one end of said spindle, depending weighted links secured to said sleeve portion, and a circuit having a separate self-contained switch means having enclosed circuit .making and breaking means positioned adjacent said sleeve, said ball pointed sleeve contacting said switch in substantially friction free contact, said spindle, sleeve and weighted links thereon being driven at a predetermined rate by said thread during a proper stitching operation so that the said sleeve may move in the direction of the switch due to centrifugal. force of the weights rotating about the spindle and actuate the said switch enabling the sewing operation to continue so long as the proper stitching is performed at the predetermined rate and to stop the sewing operation whenever the linear speed of the thread is decreased due to an improper stitching operation.

6. A stop mechanism for a sewing machine to automatically stop the sewing operation whenever improper stitching occurs comprising a frame adapted to be mounted to a sewing machine, a governor including a rotatable spindle mounted on said frame in the path of the needle thread and driven in response to the linear speed thereof, a rotatably and slidably mounted sleeve portion having a switch actuating ball point positioned on one end of said spindle, depending weighted links secured to said sleeve portion, a bar fixed to said spindle, connecting links pivoted to said bar at one end and pivoted to an intermediate portion of said weighted links, and a circuit having a microswitch means positioned adjacent said sleeve, said ballpointed sleeve contacting said switch in substantially friction free contact and said spindle, sleeve and weighted links thereon being driven at a predetermined rate by said needle thread during a proper stitching operation, so that the said ball-pointed sleeve moves toward said microswitch means due to centrifugal force of the weights and actuates the said switch means to enable the sewing operation to continue so long as the proper stitching is performed at the predetermined rate and to stop the sewing operation whenever the linear speed of the thread is decreased due to an improper stitching operation.

7. A stop mechanism for a sewing machine to automatically stop the sewing operation whenever improper stitching occurs comprising a frame adapted to be mounted to a sewing machine, a governor including a rotatable spindle mounted on said frame in the path of the needle thread and responsive to the linear speed thereof, a rotatably and slidably mounted sleeve portion having a switch actuating ball point positioned on one end of said spindle, depending weighted links secured to said sleeve portion, a transverse bar fixed to said spindle, depending connecting links pivoted to said bar at one end and pivoted to an intermediate portion of said Weighted links, a circuit having a mercury switch means therein, means carrying said switch pivotally mounted adjacent said sleeve to be engaged thereby, and adjusting means on said switch carrying means, said spindle, sleeve and weighted links thereon being driven at a predetermined rate by said needle thread during a proper stitching operation, so that the said sleeve may move in the direction of the switch due to centrifugal force of the weights and actuate the said switch carrying means and switch thereon to enable the sewing operation to continue so long as the proper stitching is performed at the predetermined rate and to stop the sewing operation whenever the linear speed of the thread is decreased due to an improper stitching operation.

8. In a sewing machine having a driving means and a controller therefor, the improvement wherein an auto matic stop means is provided to automatically stop the drive means, thereby stopping the sewing operation whenever improper stitching occurs, said stop means including a solenoid cooperating with said controller to release the same from a driving position, a first normally open self-contained switch and second normally closed selfcontained switch having enclosed circuit making and breaking means, actuation of said controller to driving position closing said first switch to establish a release circuit including said second switch and said solenoid, a governor mounted on said machine in the path of the needle thread and responsive to the linear movement of a thread, said governor having a rotatable spindle, a slidable sleeve on said spindle and rotatably mounted therewith, depending weighted links secured to said sleeve,

a bar fixed to said spindle below said slidable sleeve having depending, links, connected at one end thereto and connected. atthe other end to an intermediate portion of, said weighted links so that the centrifugal force imparted to the Weighted links due to the rotation of the spindle by the needle thread causes the slidable sleeve to move upwardly on said spindle, said governor actuating said second switch to open the release circuit upon reaching a predetermined thread speed, said second switch closing said solenoid circuit when the thread speed falls below said predetermined speed, due to an improper stitching operation, to cause said solenoid to be energized to release said controller and stop the drive means.

References Cited in the file of this patent UNITED STATES PATENTS Parsons et a1. July 24, 1888 Poirier Feb. 11, 1913 Rosenman Nov. 1, 1927 Moser Aug. 5, 1941 Boyden et al June 1, 1948 Olcott Feb. 15, 1949 Rosenman Oct. 17, 1950 Gilliam June 17, 1952 Hair May 19, 1953 Williams Oct. 11, 1955 

